Appearing on The Jeremy Kyle show, Bobby revealed that he'd discovered such a list made by his girlfriend Penny on her laptop.
The scorned boyfriend also admitted he'd previously taken her back after she had a three-month affair.
When he found the list, Bobby was horrified to see it listed Penny's conquests in chronological order – and that there were names after his.
He told Jeremy: "I found a file on her computer. It listed the amount of people she's had sex with, kissed and fore played in date order.
"I was 13 – but there were people below me. There were two other people she had had sexual contact with since me that she hadn't told me about."
But Penny insisted she only made the list because she couldn't remember everyone she'd slept with when a friend asked.
The couple both took lie detector tests, with Penny confessing she doesn't trust Bobby either.
But, in a twist that nobody could have predicted, it was revealed Bobby had also cheated when he failed his own test.
Bobby and Penny have a two-year-old son who lives with Bobby's dad.